Lift beam assembly



July 30, 1963 R, 1 WEBB 3,099,049

LIFT BEAM ASSEMBLY Filed May 5, 1962 44 4 ROBERT l.. WEBB y 34.JNVENTOR. 3%! v FIGA BY fsa, M

AGENT 3,099,049 LIFT BEAM ASSEMBLY Robert L. Webb, Oklahoma City, Okla.Filed May 3, 1962, Ser. No. 192,102 3 Claims. (Cl. 2li- 16) The presentinvention relates to tornado and bomb shelters, or the life, and moreparticularly to a means for opening the stairwell cover therefor.

Most shelters and particularly bomb and fall-out shelters are equippedwith a stairwell for egress and ingress which is usually equipped with arelatively heavy door. The doors are horizontally disposed or nearly soand it is desirable that some means be provided for assisting theoccupants in opening the door from the outside or inside of the shelter.

'It is, therefore, the principal object of this invention to provide -aspring actuated lift assembly which will bear a major portion of theweight of the entrance door for a bomb shelter, or the like, in theopening and closing action of the door.

Another object is to provide a device of -this class which is relativelysmall and yet lsturdily constructed and which will last substantiallythe life of the shelter.

An additional object is to provide a device of this class which may beeasily connected to the stairwell and door of existing shelters.

Still another object is to provide a door lifting device which includeslatch means for holding the door in opened position.

The present invention accomplishes these and other objects byinterconnecting a pair of tubular members to a door and stairwell. Thepair of members are mounted in telescoping relation with a helicalexpansion spring surrounding the inner member for normally urging themembers apart.

Other objects will be apparent from the following description when takenin conjunction with the accompanying single sheet of drawings, wherein:

FIGURE l is a side elevational View, partly in section, illustrating thedevice in door opened position and showing, by dotted lines, therelative position of the door and device when the door is closed;

FIGURE 2 is a ltop plan View of the device illustrating the manner ofits connection with the door;

FIGURE 3 is a horizontal cross-sectional View, partly in elevation,taken substantially along the line 3 3 of FIG. l; and,

FIGURE 4 is a fragmentary vertical cross-sectional View takensubstantially along the line 4 4 of FIG. 1.

Like characters of reference designate like parts in those figures ofthe drawings in which they occur.

'In the drawings:

'I'he reference numeral 10 indicates one side of a bomb shelterstairwell having a wall portion 12 integral with a step 14 `and having`a door 1'6 hingedly connected, as at 18, to the upper and outer edgesurface of the stairwell wall 12. The reference numeral indicates thedevice, or hft beam, as a whole, which is cylindrical in generalconguration and includes an outer tubular member 22 which telescopinglyreceives an inner tubular member 24. The upper end of the outer member20, las seen in FIG. 1, is provided with a transversely extending anchorpin or bolt 26 which is extended through a transverse arcuate slot ."29formed inthe free end portion of an arm 2S rigidly connected at itsother end to the lower surface of the door 16. A pair of bushings 30,surrounding the bolt 26 on either side of the arm 2S, guide the latterinto a slot 32 formed in the upper end surface of the outer member 20when the door is in open position. A mounting tube 34 is telescopinglyreceived within the depending end of the inner tube 24. The dependingend of the mounting Patented July 30, 1963 ice tube is hemispherical inshape and is centrally apertured for engagement over the upstanding endof an anchor pin 36 inserted into the upper surface of the step 14-adjacent the wall 12. A bearing washer 38 is interposed between thehemispherical end of the mounting tube and the upper surface of the step14. A thrust washer 40 surrounds the mounting tube and is secured -tothe depending end of the inner tube 24. The mounting tube 34 is providedwith a series of transverse apertures `42 for removably receiving 'a pin44 to adjust the length and lifting moment of the device 20 with respectto the lower surface of the door.

A helical expansion 'spring 47 surrounds the tube 24 and is interposedbetween the thrust washer 40 and a thrust plate 46 held in place withinthe upper end portion of the tube 22 by a bolt 49.

A substantially U-shaped latch 4S, having its respective leg endportions connected by a cross bar 50, is pivotally connected to the tube22 at a selected point intermediate its ends by latch pins 52. The crossbar 50 contacts Aand engages a hook portion 54, formed on the end of acatch 56, secured to the upper edge surface of the stairwell 12. Ahandle portion 58, secured to the bight of the U-shaped latch 48,permits manual release of the latch from the catch. A cooperatingarcuate free end edge 57 of the catch contacts the tube 22 to form astop when the door is in open position.

When the door is in closed position, as shown by dotted lines (FIG. 1),the anchor pin 26 is positioned in the end portion of the slot 29nearest the door 16. In this position the spring 47 is compressed andits full lifting force is utilized when the door starts its movementtoward open position. The arrangement of the components `is such thatthe linear change of spring force during extension and compression, indoor yopening and closing, acts through a moment arm of varying length.The angular position of the arcuate slot 29 increases and decreases thetension on the spring 47 and provides the correct moment through allangles of door movement and minimizes the external efort required toopen the door or support the door while closing. 'Ihe device 20 retractsto become nearly flush with the wall 12 and leaves the stairwell clearwhen the door is in an open position. In the open position, the devicelacts as a beam to hold the door in a vertical plane. A lug 59, securedto the tube 22 above the latch 48 maintains the door in open positionagainst wind pressure on the door.

A downward and side force is exerted on the mounting pin 36 at alltimes. Therefore, the necessity for tension type fasteners iseliminated. Installation of the device is thereby simplified and it isparticularly adaptable to existing masonry structures.

Obviously the invention is susceptible to some change or alterationwithout defeating its practicability, and I therefore do not wish to beconiined to the preferred embodiment shown in the drawings and describedherein, further than II am limited by the scope of the appended claims.

I claim:

l. A lift assembly for a horizontal door covering a stairwell,comprising: a pair of elongated tubular members joined in telescopingrelation; a helical expansion spring surrounding the innermost one ofsaid telescoping members; mounting means pivotally connecting one end ofthe innermost -said member to the upper surface of one step in saidstairwell, said mounting means comprising a mounting tube telescopinglyreceived bythe depending end portion of said inner tube, said mountingtube having an apertured hemispherical depending end, an anchor pinsecured by one end portion within said one step of said stairwell andprojecting upwardly into said mounting tube, and a bearing washerinterposed between the upper surface of said step and the hemisphericalend of said mounting tube; means pivotally connecting the uppermost endof said outer member to the lower surface of said door; and latch meanspivotally connected to said outermost member intermediate its ends .andreleasably engaged with the Wall forming one side'of the stairwell whenthe door is in open position.

2. A lift assembly for a horizontal door vcovering a stairwell,comprising: a pair of elongated tubular members joined in telescopingrelation; a helical expansion spring surrounding the innermost one ofsaid telescoping members; mounting means pivotally connecting one end ofthe innermost said member to the upper surface of one step in saidstairwell, said mounting means comprising a mounting tube telescopinglyreceived by the depending end portion of said inner tube, said mountingtube having an apertured hemispherical depending end, an anchor pinsecured by one end portion within said one step of said stairwell andprojecting upwardly into said mounting tube, and a bearing washerinterposed between the upper suface Vof said step `and the hemisphericalend of said mounting tube; connector means pivotally connecting theuppermost end of said outer member to the lower surface of said door,said connector means comprising an arm rigidly connected at one end tothe adjacent surface of said door, said arm having an arcuate slot inits free end portion, yand a bolt transversely extending through saidouter member and slidably received by the slot in said ann for varyingthe compression of said spring during the opening and lclosing action ofsaid door; and latch means pivotally connected to said outermost memberintermediate its ends and releasably engaged with the wall forming oneside of the stairwell when the door is in open position.

3. A lift assembly for a horizontal door covering a stairwell,comprising: a pair of elongated tubular members joined in telescopingrelation; a helical expansion spring surrounding the innermost one ofsaid telescoping members; mounting means pivotally connecting one end ofthe innermost said member to the upper surface of one step in saidstairwell, said mounting means comprising a mounting tube telescopinglyreceived by the depending end portion of said inner tube, said mountingtube having an apertured hemispherical depending end, an anchor pinsecured by one end portion within said one step of said stairwell .andprojecting upwardly into said mounting tube, yand a bearing washerinterposed between the upper surface of said step and the hemisphericalend of said mounting tube; connector means pivotally connecting theuppermost endof said outer member to the lower surface of said door,said connector means comprising an arm rigidly connected at one end tothe adjacent surface of said door, said arm having an arcuate slot inits free end portion, and a bolt transversely extending through saidouter member and slidably received by the slot in said `arm for varyingthe compression of said spring during the opening and closing action ofsaid door; and latch means pivotally connected to said outermost memberintermediate its ends and releasably engaged with the Wall forming oneside of the stairwell when the door is in open position, said latchmeans comprising a U-shaped latch forming a handle and having its legportions pivotally connected to opposing ysides of the outermost one ofsaid pair of tubular members, a bar interconnecting the ends of the legsof said U-shaped latch opposite the handle, and a catch secured to saidwall forming one side of Said stairwell and releasably engaged with saidbar, said catch having an arcuate free end edge engagable with aperipheral portion of the outermost one of said pair of tubular memberstto form a stop.

References Cited in the le of this patent UNITED STATES PATENTS1,090,697 Eddelman Mar. 17, 1914 2,643,420 Schwarty June 30, 19532,939,738 Lyons June 7, 1960

1. A LIFTER ASSEMBLY FOR A HORIZONTAL DOOR COVERING A STAIRWELL,COMPRISING: A PAIR OF ELONGATED TUBULAR MEMBERS JOINED IN TELESCOPINGRELATION; A HELICAL EXPANSION SPRING SURROUNDING THE INNERMOST ONE OFSAID TELESCOPING MEMBERS; MOUNTING MEANS PIVOTALLY CONNECTING ONE END OFTHE INNERMOST SAID MEMBER TO THE UPPER SURFACE OF ONE STEP IN SAIDSTAIRWELL, SAID MOUNTING MEANS COMPRISING A MOUNTING TUBE TELESCOPINGLYRECEIVED BY THE DEPENDING END PORTION OF SAID INNER TUBE, SAID MOUNTINGTUBE HAVING AN APERTURED HEMISPHERICAL DEPENDING END, AN ANCHOR PINSECURED BY ONE END PORTION WITHIN SAID ONE STEP OF SAID STAIRWELL ANDPROJECTING UPWARDLY INTO SAID MOUNTING TUBE, AND A BEARING WASHERINTERPOSED BETWEEN THE UPPER SURFACE OF SAID STEP AND THE HEMISPHERICALEND OF SAID MOUNTING TUBE; MEANS PIVOTALLY CONNECTING THE UPPERMOST ENDOF SAID OUTER MEMBER TO THE LOWER SURFACE OF SAID DOOR; AND LATCH MEANSPIVOTALLY CONNECTED TO SAID OUTERMOST MEMBER INTERMEDIATE ITS ENDS ANDRELEASABLY ENGAGED WITH THE WALL FORMING ONE SIDE OF THE STAIRWELL WHENTHE DOOR IS IN OPEN POSITION.